An electric motor has a movable part referred to as a rotor and a stationary part referred to as a stator. The rotor is connected to a load which is to be moved by the motor. Generally the rotor is arranged to rotate relative to the stator. The rotor and the stator generate an electromagnetic interaction to move the rotor and thus drive the load. According to a position relation between the rotor and the stator, motors are also classified into an inner rotor type and an outer rotor type. As the name implies, in an inner rotor type motor, the rotor is disposed inside the stator. That is, the stator is disposed about the outside of a core of the rotor.
In a known brushless DC motor having a permanent magnet rotor of the inner rotor type, the stator has stator windings wound about a stator core which is fitted to a cylindrical outer housing. To provide a strong connection between the housing and the stator core, the core may be fixed to the housing using glue or an interference fit. However, glue may deteriorate over time. To ensure a strong interference fit, the housing may be heated to cause thermal expansion and then the core is pressed into the housing. This produces a strong connection but it is not production friendly and, as the size of the stator core and the housing is hard to precisely control, the inner surface of the housing may be scratched and scrapings may be left inside the housing, which may affect operation of the motor.